Synethic apparatus for inspection of blood

ABSTRACT

A blood analyzer system incorporates a conveyor for handling and transporting sample blood through at least one blood analyzer and an automatic blood smear generator under the control of a programmable controller. Blood samples are stored in sample containers having identifiers for the sample blood that they contain. These sample containers are transported through the system in protective racks that permit the reading of the identifiers. The results of analysis by one or more blood analyzers in the system determines the need for performing or omitting subsequent operations on a particular sample blood. When a smeared blood sample is to be made, the controller assures that the smear thickness is consistent with other samples regardless of the thickness or viscosity of the sample blood. If the system fails to make a required smeared blood sample, a detector sounds an alarm, warning of a system failure.

BACKGROUND OF THE INVENTION

This is a divisional of application Ser. No. 07/577,689 filed on Sep. 4,1990 and now U.S. Pat. No. 5,209,903 issued May 11, 1993.

The present invention relates to a general blood analyzing system andmore particularly to an integrated general blood analyzing system thatcomprises a sample (sample)-rack transportation system, blood analyzers,and an automatic smearing device.

Blood analyzers which take blood samples from a sample container andthen classify and count blood corpuscles are well known, as are devicesthat make a smear sample by smearing the blood sample on a slide glass.

Japanese Patent Laid-open Publication No. 63-217273 discloses a systemthat combines more than one blood analyzer for the performance of avariety of tests with a transportation device for an array of bloodsamples in sample containers. However, this system does not include thepreparation of blood smears for further examination, requiring that theblood smears be made by hand or that the samples be transferred to otherdevices for the preparation of smears.

Automatic smearing devices for preparing blood smears on slides are alsowell known. Japanese Examined Patent Publications No. 61-45769, No.62-16380, and Japanese Laid-Open Patent Publication No. 57-171259disclose automatic apparatus for preparing blood smears. Publication No.61-45769, describes an apparatus, wherein at least one of a movingvelocity and an angle of a pulled glass is varied continuously as it isdrawn over a blood specimen in order to make the thickness of a sampleblood smear constant. Publication No. 62-16380 describes an apparatuswherein the rotating speed of a motor is controlled in order to disperseblood corpuscles evenly on a slide glass. Publication No. 57-171259,describes an apparatus wherein the angle of a pulled glass decreasesgradually as it is drawn over a blood specimen so as to minimize thechanges in smear thickness.

In the spinner method, a drop of blood is placed on the surface of aglass slide, which then is spun so that the blood is spread over thesurface and smeared by centrifugal force. The wedge method, on the otherhand, is a method in which a glass slide is drawn through a blood samplealong its long side to smear blood on its surface.

However, these methods do not provide consistency between smear samplesbecause they do not adjust for variations in specific character betweenblood samples.

A smeared sample rack is provided into which smeared slides are placed.The smeared samples are then dipped in a dyeing liquid along with thesmeared sample rack.

The smeared sample rack needs a handle with which it can be carried ordipped into a dyeing liquid. When the rack is held by its handle, thehandle must be centered. However, in an automatic loading device therack handle must be movable so as not to interfere with loading of therack. In addition, the handle must always take the same position eachtime the rack is loaded to facilitate the handling of loaded racks.Conventional racks do not meet these requirements.

For quality analysis, the thickness of prepared blood smears must beconsistent from smear to smear, regardless of the great variety ofpossible blood consistencies.

Japanese Examined Patent Publication No. 61-45769 discloses a method toachieve the required thickness in which at least one of the angle or thevelocity of a smearing glass is changed continuously. However, thisdevice cannot automatically determine the consistency of the blood to besmeared and must be adjusted for separate blood samples.

Separate devices for measuring blood viscosity are well known. Forexample, a method is known that determines blood viscosity by measuringits flow time through a measured length of capillary tubing. It is notclear how these conventional apparatuses could be installed in anautomatic smearing device. If such a blood viscosity measuring devicewere integrated into an automatic smearing device, the device would becomplex, large, slow and costly.

Although an automatic smearing device employs automated smearingpreparation processes, various monitoring functions are required.Detection of the presence of a smear is an example. If there is no bloodsmear on a slide to be examined because of a machine malfunction, awarning must be issued.

A conventional method for detecting a blood smear focuses a knownintensity light through a smeared slide and measures the intensity ofthe light transmitted by the slide. The light loss through a bloodsmeared slide is greater than that through a clean slide. However,because of the variety of smears produced, a very thin smear might notbe detected.

Conventional methods for printing an identifier on a blood smeared slideinclude a printer disclosed in Japanese Laid-Open Patent Publication No.55-48655 that uses a printing plate and ink.

The major problem presented by the use of a printing plate and ink isthat because the smeared specimen is dyed following blood samplesmearing and the dyeing liquid contains alcohol, identifying marksimprinted in ink may wash off during the dyeing process.

Another approach is to imprint the identifier with a thermal printer ona resin-coated portion of a slide. This method requires that expensive,specially prepared slides be used for preparing smeared blood samples.

The use of a dot matrix impact printer for imprinting identifiers onslides is also well known. Dot matrix impact printers print using aprinter head that strikes an ink ribbon with pins of a printer head toleave ink dots on the slide being identified.

Problems that limit the effectiveness of conventional dot matrix impactprinters include the breaking of slides as they are impacted by printerhead pins and the short life of the printer head pins when used in thisapplication.

Another major problem of conventional dot matrix impact printers is thatthey do not provide good penetration of ink into the hollows of theground glass portion of the slides on which the printing is done. Thisallows the ink identifier to be washed away during dyeing.

OBJECTS AND SUMMARY OF THE INVENTION

Accordingly, it is an object of the invention to provide a bloodanalyzer system that overcomes the drawbacks of the prior art.

It is a further object of the invention to provide a blood analyzersystem incorporating a fully integrated smear generator for making bloodsmears automatically as required.

It is a still further object of the invention to provide a smeargenerator that automatically adjusts to the thickness of the variousblood samples to make smears of consistent thickness.

It is a still further object of the invention to provide improved meansfor the convenient and safe handling of blood samples.

Briefly stated, the present invention provides a blood analyzer systemthat incorporates means for handling and transporting sample bloodthrough at least 1 blood analyzer and an automatic blood smear generatorunder the control of a programmable controller. Blood samples are storedin sample containers having identifiers for the sample blood that theycontain. These sample containers are transported through the system inprotective racks that permit the reading of the identifiers. The resultsof analysis by one or more blood analyzers in the system determine theneed for performing or omitting subsequent operations on a particularsample blood. When a smeared blood sample is to be made, the controllerassures that the smear thickness is consistent with other samplesregardless of the thickness or viscosity of the sample blood. If thesystem fails to make a required smeared blood sample, a detector soundsan alarm, warning of a system failure.

According to an embodiment of the invention, there is provided apparatusfor automatic processing of blood, comprising: at least one bloodanalyzer for analyzing a sample blood, at least a second bloodprocessing device, and means for actuating the second blood processingdevice in response to a result from the at least one blood analyzer.

According to a feature of the invention, there is provided an automatedhandling device for handling sample containers, comprising: the samplecontainers including identifying markings thereon, a conveyor, a samplerack movable on the conveyor for containing at least one of the samplecontainers, a reader effective for reading the identifying markings, andmeans for rotating the at least one sample container about an axiseffective to bring the identifying markings into a position readable bythe reader.

According to a further feature of the invention, there is provided anautomated smear generator comprising: a conveyor, means for deliveringat least one slide to the conveyor, at least first and second positionsalong the conveyor, means at the first position for depositing a blooddrop on the at least one slide, means at the second position forsmearing the drop of blood to produce a smeared blood sample, and meansfor unloading the at least one slide from the conveyor.

According to a still further feature of the invention, there is providedapparatus for printing information on a glass slide, the glass slideincluding a frosted area, comprising: the frosted area including aplurality of projections, an impact printer, the impact printerincluding an impacting element, an ink carrier between the impactingelement and the frosted area, and the impacting element being effectiveto strike the ink carrier with sufficient force to at least partly crusha substantial number of the plurality of projections, whereby the ink istransferred to the frosted area in a pattern determined by the impactingelement.

According to a still further feature of the invention, there is provideda smear detector for detecting a smeared blood sample on a slide,comprising: a light source, a light detector, a light beam passing fromthe light source to the light detector along an axis, the axis beinginclined at an angle to a surface of the slide, and the angle being fromabout 30 to about 75 degrees.

According to a still further feature of the invention, there is provideda slide supply device comprising: means for accepting at least one rackcontaining a plurality of slides, a slide outlet port in the rack,closing means effective to prevent the slides passing through the outletport, and cooperating means between the rack and the means for acceptingfor moving the closing means to a position permitting the slides to passthrough the outlet port.

According to a still further feature of the invention, there is providedapparatus for detecting the presence of a slide, the slide including afrosted area comprising: a light source projectable on the frosted areawhen a slide is present, a light detector effective for detecting lightreflected from the frosted area when the slide is present, and the lightdetector being in an alarm condition when a slide is not present.

According to still another feature of the invention, there is providedapparatus comprising: a rack for holding a stack of slides, each of theslides including a frosted area thereon, a light source projectable onthe frosted area when a slide is present in the rack, a light detectoreffective for detecting light reflected from the frosted area when theslide is present, and the light detector detecting that the rack isempty when a slide is not present.

According to yet another feature of the invention, there is provided ablood preparation system comprising: means for drawing a sample of bloodthrough a tube, means for measuring a time for blood to flow through apredetermined length of the tube to produce a measured time, and meansfor using the measured time to control subsequent operations on thesample of blood.

According to a still further feature of the invention, there is provideda smearing fixture for smearing a sample blood comprising: a glassholder, the glass holder including means for holding a smearing glass, apivotable support for the glass holder, resilient means for urging thesmearing glass into contact with a surface of a slide, the contact beingat an angle with respect to the surface, and means for moving thesmearing fixture up and down whereby the angle may be varied.

According to a still further feature of the invention, there is provideda smeared sample rack comprising: a rack body, a handle, cooperatingmeans in the handle and the rack body for pivotably mounting the handleto the cassette body, the cooperating means permitting first and secondpositions for the handle, the first position being substantiallyvertical, and the second position being inclined at an angle from thevertical.

The above, and other objects, features and advantages of the presentinvention will become apparent from the following description read inconjunction with the accompanying drawings, in which like referencenumerals designate the same elements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a conventional slide rack.

FIG. 2 is a side view of a conventional smear detector.

FIG. 3 is a magnified view of FIG. 2 showing blood particle distributionon a slide with a thick smear.

FIG. 4 is a magnified view of FIG. 2 showing blood particle distributionon a slide with a thin smear.

FIG. 5 is a system plan view of an embodiment of the invention.

FIG. 6 is a side view of a rotating means for the sample containersshown in FIG. 5.

FIG. 7 is a perspective view of the smear generator.

FIG. 8 is an end view of the conveyor belt as seen from arrow A in FIG.7.

FIG. 9 is a perspective view of an embodiment of the slide cassetteaccording to the invention.

FIG. 10 is a perspective view of the slide supplying turntable.

FIG. 11 is a cross section of the turntable supplying a blank slide tothe conveyor.

FIG. 12 is a plan view of an embodiment of the turntable slide supplyingdevice according to the invention.

FIG. 13 is a flow diagram of a hydraulic circuit to drop a blood sampleon a slide.

FIG. 14 is a flow diagram of another embodiment of a hydraulic circuitto drop a blood sample on a slide with blood viscosity detection andwashout capability.

FIG. 15 is a detailed view of the blood flow detection sensors shown inFIG. 16.

FIG. 16 is another embodiment of a hydraulic circuit to drop a bloodsample on a slide using viscosity detection and washout capability.

FIG. 17 is a cross-sectional view, taken in the direction B in FIG. 7,of an automatically adjustable blood smearing device shown in thesmearing position.

FIG. 18 is a cross-sectional view, taken in the direction B in FIG. 7,of an automatically adjustable blood smearing device shown in thewashing position.

FIG. 19 is a perspective view of an embodiment of the diagonallypositioned smear detector according to the invention.

FIG. 20 is a graph representing the relationship between an incidenceangle and the signal-to-voltage level detected by the diagonallypositioned smear detector.

FIG. 21 is a perspective view of an embodiment of the smeared slidesample code printer.

FIG. 22 is a schematic section view of the surface condition on theslide before impact of the printer pins.

FIG. 23 is a schematic section view showing a printed condition on aslide.

FIG. 24 is front view of an embodiment of a smeared sample rackaccording to the invention.

FIG. 25 is a plan view of the smeared sample rack.

FIG. 26 is a side view of the smeared sample rack.

FIG. 27 is a left side view of the upper part of the smeared sample rackaccording to another embodiment of the invention.

FIG. 28 is an upper left side view of the smeared sample rack accordingto another embodiment of the invention.

FIG. 29 is a plan view of a transportation unit of smeared sample racksin the smear generator.

FIG. 30 is a functional block diagram of a smear generator according toan embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIG. 1, there is shown a cassette 10 of the prior art.Cassette 10 is a rectangular tube that comprises a right side wall 12, aleft side wall 14 spaced apart by a rear wall 16 secured by screws 17. Asliding front wall 22 closes a front of cassette 10. A front bottom wallsection 18 is disposed across a forward end of a bottom opening ofcassette 10, while a rear bottom wall section 20 is disposed across arear end of the bottom opening, so as to define a broad opening of thebottom of cassette 10 between them. Front bottom wall section isU-shaped leaving an open space at the front bottom of cassette 10.

Front and rear thickened edges 24 and 26, respectively, of left andright side walls 14 and 12 are thickened for increased rigidity andproject downwardly slightly more than the thickness of a slide to formnotches 30 with front and rear bottom wall sections 18 and 20. Notches30, together with the bottom of cassette 10, forms an outlet port 32.

Sliding front wall 22 is supported in opposing grooves 34 on the innerfacing surfaces of front thickened edges 24 so as to be slidable up anddown to cover opening 36. Recessed notches 38 at the bottom fronts offront thickened edge 24 and the bottom rear of thickened edge 26stabilize an installed cassette 10.

Cassette 10 is loaded by raising sliding front wall 22 and inserting astack of slides 28 into cassette 10 through opening 36. Duringoperation, slides are taken one at a time through outlet port 32 in thedirection of the arrow.

Cassette 10 has capacity of about 100 slides 28. Because slides 28 havehighly polished surfaces, they tend to bind. When cassette 10 is nearlyfull, the weight of stacked slides 28 causes the bottom most slide 28 toresist being removed through outlet port 32.

On the other hand, when there are only a few slides in cassette 10 thebottom most slide 28 tends to fall out of cassette 10 through slideoutlet port 32 whenever cassette 10 is tilted. This makes it awkward tohandle cassette 10.

Referring to FIG. 2 there is shown a blood smear detector 40 of theprior art. Slide 28 has a blood smear 42 on a surface facing lightemitter 45. Light emitter 45 emits a light beam 46 toward the surface ofslide 28. On the side of slide 28 opposite light emitter 45 a lightdetector 47 is positioned to form a path for light beam 46 between lightemitter 45 and light detector 47 that is approximately perpendicular toa surface of slide

During smear detection, when the blood smear is thin (as shown in FIG.4), light beam 46, transmitted through a blood smeared slide 28, isalmost as intense as light beam 46 transmitted through a clean slide. Asa result, a very thin blood smear 42 may not be detected.

When blood smear 42 is thick (as shown in FIG. 3) blood smeared slide 28transmits much less light than a clean slide 28 making the detection ofblood smear 42 certain. The prior art described herein is unacceptable,because this device is able to detect only relatively thick blood smears42.

Referring to FIG. 5, a loader 44 of a blood analyzer system 49 is loadedwith a plurality of sample racks 48 to be unloaded onto an entry end ofa conveyor 50 that is in a position proximal to loader 44. Each samplerack 48 contains a plurality of sample containers 52, which may be testtubes or the like, each filled with a blood sample for analysis.

The contents of sample container 52 can be analyzed with or without arubber stopper 54 in its opening. In either case, a blood sample in thesample container 52 is drawn using conventional means.

Conveyor 50 transports sample racks 48 through at least one of a bloodcorpuscle analyzer 56, a reticulate red blood corpuscle analyzer 58, anda smear generator 60. Other devices may be employed with the abovedevices without departing from the spirit of the invention. All of theoperations performed by the invention are controlled by a controller 62,which continually monitors the process.

Following the last blood analysis device, sample racks 48 reach adischarge end 64 of conveyor 50, where an unloader 66 disposed at thedischarge end 64 of conveyor 50 loads sample racks 48 for removal.

A sample rack 48 carries more than one sample container 52. Each samplecontainer 52 has an identifying bar code label (not shown) that can beread from the outside of sample rack 48. Each sample rack 48 includes abar code access window 68 on its side for each sample container 52 itcan hold. Bar code readers 70, located at each process position, viewthe bar codes through the bar code access windows 68. Japanese PatentLaid-open Publication 63-217273 discloses an example of this.

Sample containers 52 are placed in sample racks 48 in generally randomrotational orientations. Thus, a bar code on a sample container 52 maynot be turned to face its bar code access window 68. To assure that thebar code label on sample containers 52 is properly read at each processposition, sample containers 52 are rotated within sample rack 48 by arotator 71 shown in FIG. 6.

Referring to FIG. 6, a rubber cylinder 72 of rotator 71 is axiallysuspended from a shaft 74. Shaft 74 is rotatably supported by a bearing76 in a support 78. A pulley 80 on shaft 74 is rotated by a motor (notillustrated) through a belt 82, causing rotation of rubber cylinder 72.Rotator 71 is moveable up and down with assistance of another drivingsource (not illustrated) to engage and release a rounded bottom ofrubber cylinder 72 with rubber stopper 54 of sample container 52.

Rotator 71 is lowered to engage rubber cylinder 72 with rubber cap 54.Rubber cylinder 72 is also rotated slowly, thus slowly rotating samplecontainer 52. As sample container 52 rotates, a bar code 84 can be readregardless of the initial orientation of sample container 54. A stop 86at each processing location holds sample rack 48 in a fixed position onconveyor 50 until the process step at that location is completed.

Referring to FIG. 7, supplier 88 of smear generator 60 supplies oneslide 28 at a time from the top of a slide stack 92 to a slide conveyor94. Slide 28 may be 76 mm×26 mm×0.9-1.2 mm in size and have a frostedarea 96 on which an identifier may be printed.

With slide stack 92 in place, a stack lifter 100 lifts slide stack 92.Supplier 88 shifts to the right to push a topmost slide 28 onto an entryend 106 of a conveyor 94. Conveyor 94 steps slides 28 one after anotherto each stage of blood smear generation on an endless conveyor belt 108.Conveyor belt 108 has a plurality of protrusions 110 that define spaces112 between them for transporting slides 28. A roller 114, disposed ateach end of conveyor 94, both supports and drives conveyor belt 108.

Referring now to FIG. 8, there is shown a view of conveyor 104 as seenin the direction of arrow A of FIG. 7. Roller 114 is rotatably supportedby a shaft 116, axially attached to an end 122 of roller 114. A pulley120 is affixed to the end of shaft 116. A timing belt 118 is drivendiscontinuously (by conventional means not shown) to step conveyor belt108 one slide space at a time. Disk shaped plates 124 are axiallysupported by shaft 116 so that they support opposite edges of conveyorbelt 108. Supporting plates 126, disposed on opposite sides along theentire length of conveyor belt 108, support ends of slides 28, as theyare pushed along by protrusions 110.

Referring again to FIG. 7, major blood smear generation devices, to bedescribed below, are disposed along conveyor 94. In the illustration,five slides 28a through 28e are shown in place on conveyor 104 forprocessing by these devices. Slide 28a, positioned at the left end ofconveyor 94 is in a waiting position. Slide 28b is in a positionreceiving sample blood drops 128 from a dropper 130. A smearing glass132 smears blood drops 128 on slide 28b, to produce a smeared bloodsample 138, as will be described.

A dropper washer 134 and a smearing glass washer 136 are locatedproximal to dropper 130 and smearing glass 132, respectively, to washthem between the preparation of smeared blood samples.

Smeared blood sample 138 on slide 28c is dried by a fan 140. Slide 28dis imprinted with an identifier by a printer 142 on frosted area 96,while slide 28e, with smeared blood sample 138 and identifier imprintthereon is loaded into a smeared sample rack 144 by a mechanical hand146.

Smeared sample rack 144 is moved between loading platform 148 and anunloading platform 149 on a track 147 by a hold and move means 150. Holdand move means 150 holds smeared sample rack 144 using arms 152. Holdand move means 150 is moved along track 147 on a guide 154 positionedparallel to track 147 by any conventional device such as, for example, alead screw 156. A conventional drive means (not shown) operates leadscrew 156.

Referring to FIG. 9, a cassette 10', according to the present invention,is the same as the prior art cassette 10 shown in FIG. 1, and describedin the foregoing except for differences recited in the followingparagraphs. Parts of cassette 10' that are the same, and have the samefunctions, as previously described are not described again.

A left side wall 14' includes a recess 157. A shutter 158 is disposed inrecess 157. Recess 157 is deeper than the thickness of shutter 158 sothat shutter 158 can move smoothly within it. The shutter 158 has twoslots 167. Two props 159, vertically positioned at the forward andrearward edges of recess 157, through two slots 167 slidably support andallow up and down motion of shutter 158.

A deep cutaway 160 above slide outlet port 32 allows a contactor 161(shown in FIG. 10) of a turntable 162, to be described later, to raiseshutter 158. Shutter 158 opens and closes outlet port 32. Shutter 158must be fully opened to allow a slide 28 to be removed from cassette 10.In this embodiment, shutter 158 moves up and down on tracks 163 to openand close slide outlet port 32.

As would be clear to one skilled in the art, shutter 158 may move fromside to side or be hinged without departing from the present invention.

Shutter 158 is normally moved to the closed position by its own weightto cover outlet port 32, thus preventing the bottommost slide 28 fromsliding out of cassette 10 when carried. When shutter 158 is moved upfrom the bottom along tracks 163, formed between left side wall 14' andprops 159, slides 28 can be slid out of outlet port 32 one at a time.

Referring to FIG. 10, turntable 162 of slide supply device 165 includesthree cassette receivers 164 into which a cassette 10' loaded withslides 28 can be inserted. Right and left side walls 12 and 14' ofcassette 10 each have two notches 38 (as shown in FIG. 9) that entercassette receivers 164 to stabilize cassettes 10'. Contactor 161,located inside cassette receivers 164 contacts, and upwardly liftsshutter 158 of installed cassette 10'.

Referring now to FIG. 11, there is shown a section view of turntable 162with cassette 10' in place in cassette receiver 164. When cassette 10'is set in cassette receiver 164, contact of shutter 158 of cassette 10'with contactor 161 pushes shutter 158 upward, opening slide outlet port32. Because cassette 10' has an outlet port 32 only on one side,contactor 161 makes it impossible for cassette 10 to be installed incassette receiver 164 incorrectly.

A slide unloader 166 is located under turntable 162 to unload slides 28from slide outlet port 32 of cassette 10', and send them to conveyerbelt 108 of conveyor 94. To accomplish this, slide unloader 166comprises a slide receiver 168 which is mounted on a support 169. Adepression 170 in slide receiver 168 has a depth that is slightly lessthan the thickness of a slide 28. A conventional up/down drive 172, anda conventional fore/aft drive 174 are connected to support 169 to liftslide receiver 168 up to engage bottommost slide 28 and to move slideunloader 166 along a path 176 to place slide 28 on conveyor belt 108.Conveyor belt 108 is stepped one space 112 following the unloading ofslide 28 from cassette 10' to present an empty space 112 to next slide28.

A sensor 178 is disposed at a side of slide receiver 168 to determinethe presence of a loaded cassette 10'.

Referring to FIG. 12, cassettes 10', which hold, for example, 100 slides28 each, are set in cassette receivers 164 in turntable 162. Turntable162 is rotatably mounted on a shaft 180. Shaft 180 is turned and stoppedby a controller/driver 182 driving a belt 184. The stop position isdetermined by sensor 178, which is oriented in an upward lookingdirection from under turntable 162, centered on the outer edge ofdepression 170 of slide receiver 168. When a cassette receiver 164 witha cassette 10' loaded with slides 28 is installed over slide receiver168, a signal from sensor 178 causes a controller/driver 182 to stopturntable 162 and to engage a bolt 186 of a lock 188 in a notch 190,thereby locking turntable 162 in place. Three notches 190 are disposedaround an edge 192 of turnable 160. Each notch 190 corresponds to one ofthe three positions in which a cassette receiver 164 can be positioned.

Any other suitable locking devices may be substituted for lock 188 andnotches can be substituted, without departing from the spirit of theinvention. For example, a lock can utilize a bolt which moves upward toengage and lock turntable 162.

Referring now to FIGS. 11 and 12, sensor 178, which may be any suitabledevice such as, for example, a photo detector 178' as shown in FIG. 10.In a convenient embodiment, sensor 178 includes a light source,projected upward, and a photodetector integrally formed therein. Sensor178 continually checks for the presence of a slide 28 in cassette 10' bysensing reflection of its light source from frosted area 96 of slide 28.When the presence of a stack of slides is sensed, the slides 28 areunloaded one by one by slide unloader 166.

When cassette 10' is empty, sensor 178 causes turntable 162 to rotate120 degrees, thereby positioning the next cassette 10' for unloading asdescribed above.

Because turntable 162 can hold three or more cassettes 10', there is noneed to stop the device when a cassette 10' is empty. The empty cassette10' can be reloaded or replaced by a loaded cassette 10' before theremaining two cassettes 10' are emptied.

Slides 28 move along path 176 under turntable 162 and slide receiver 168to reach conveyor belt 108 properly oriented for subsequent operations.

Referring to FIG. 13, there is shown a hydraulic circuit 194 fordispensing a sample blood 196 from sample containers 52 to slides 28 forsmearing. A two position valve 198 controls the flow of blood fromsample container 52 to slide 28.

A syringe operator 203 drives a piston 205 in a syringe 204 to draw andforce a sample blood through hydraulic circuit 194.

In a first position of valve 198, a port 200 is open to an inlet port202, forming a complete path for blood to be drawn from sample container52 to syringe 204. In a second position of valve 198, port 200 is opento outlet port 206, thereby forming a complete path for blood betweensyringe 204 and dropper 130 to place blood drop 128 on slide 28. Withvalve 198 in the first position, syringe 204 draws sample blood 196under control of syringe operator 203 from an open sample container 52through a thin pipette 208, or from a sample container 52' with a rubberstopper 54 through a hypodermic needle 210, an inlet tube 212, inletport 202, port 200 of valve 198, and a syringe tube 214 to syringe 204.

When syringe 204 is filled with sample blood, valve 198 is switched toits second position. Sample blood is forced by syringe 204 throughsyringe tube 214, port 200 and outlet port 206 of valve 198, and droppertube 216 to dropper 130 from which it is dropped on slide 28. In thisway, sample blood 196 is dispensed at a location that is relativelydistant from that at which it was drawn without moving connecting tubes.

Referring to FIG. 14, there is shown a schematic diagram of a secondembodiment of a hydraulic circuit 194' for dispensing sample blood 196from sample containers 52 to slides 28 for smearing.

A switching valve 198' having ports A, B, C, D, and E includes first andsecond conditions. In the first condition (as shown in FIG. 14), a portA is connected to a port B, and a port C is connected to a port D. Inthe second position, port A is connected to a port E, and port B isconnected to port C.

A first end of inlet tube 212 is connected to port A of valve 198'. Asecond end 220 of inlet tube 212 is in position to draw blood fromsample container 52. Inlet tube 212 may be a simple tube or it may havea needle 210 (shown in phantom) at end 220. The presence or absence ofneedle 210 depends on whether or not sample container 52 is sealed by arubber stopper 54 also shown in phantom. Port B of valve 198' isconnected to a first end of tube 214. A second end of tube 214 isconnected to a syringe 204, thereby communicating port B to syringe 204.A third end of tube 214 is connected to an outlet port 222 of a washervalve 224. An inlet port 226 of washer valve 224 is connected by one legof a Y-shaped tube 228 to a washer 230. A second leg of Y-shaped tube228 connects washer 230 to an inlet port 232 of washer valve 234. Anoutlet port 236 of washer valve 234 is connected to port E of valve 198'by a tube 238.

Port C is connected to a first end of dropper tube 216. A second end ofdropper tube 216 is connected to dropper 130. Dropper 130 is positionedover slide 28 to deposit a blood sample 196 for smearing. A positivepressure source 240 is connected through an inlet port 242 of an airvalve 244, outlet port 246, and a tube 248 to port D of valve 198'. Asecond positive pressure source 247 is connected through inlet port 250of an air valve 252, an outlet port 254, and an air tube 255 to washer230.

Sample sensors 256 and 258 are positioned on inlet tube 212 and syringetube 214, respectively, to send blood detection signals to a timer 260.Timer 260 determines the thickness of sample blood 196 by measuring thetime required for blood sample 196 to move between sample sensors 256and 258.

With valve 198' in the first position shown in FIG. 14, and syringe 204in the drawing mode, syringe operator 203 pulls a piston 205 in anoutward direction, causing sample blood 196 to be drawn, thus fillinginlet tube 212, valve 198', and a part of syringe tube 214 up to sensor258.

Next, switching valve 198' switches to its second position and syringe204 is activated in the discharge mode. The sample blood 196 is fedthrough valve 198' ports B and C, dropper tube 216, and dropper 130 ontoslide 28. As soon as delivery of blood drop 128 is completed, valves 252and 234 are opened to permit driving of washer fluid 259 from washer 230by pressure in positive pressure source 247, inlet port 250 of air valve252, and air tube 255 to clean the inside of tube 212, end 220 andneedle 210, if used.

Switching valve 198' returns to its initial position. Syringe 204 isreturned to the drawing mode to draw in additional washer fluid 259.Switching valve 198' switches to its alternate position, and valve 226is closed. Syringe 205 is switched to the discharge mode to drive washerfluid 259 through dropper tube 216 and dropper 130, thereby cleaningthese parts.

Switching valve 198' then returns to the initial condition, valve 252 isopen to pass air from positive pressure source 240, emptying tube 216.

First sensor 256 is located near switching valve 198' on inlet tube 212.Second sensor 258 is located near switching valve 198' on syringe tube214. First and second sensors 256 and 258 are identical, thus only firstsensor 256 is described in detail.

Referring now to FIG. 15, sensor 256, viewed from the directionperpendicular to tube 212, comprises a light emitter 262 such as an LED,a light receiver 264 such as a phototransistor, and supports 270 and272. Supports 270 and 272 support inlet tube 212. The light from lightemitter 262 illuminates inlet tube 212 through a slit 274. Inlet tube212 (as well as syringe tube 214) is made of light transmitting materialsuch as, for example, glass or transparent synthetic resin.

When a blood sample is present in tube 212, an electric signal output bylight receiver 256 is sent to a timer 260. Before drawing sample blood,tube 212 at sensor 256 contains air or washer fluid 259. Therefore, tube212 transmits light. When tube 212 is filled with sample blood 196, thelight to light receiver 264 is at least partially blocked. The resultingsignal to timer 260 indicates the presence of sample blood. The timeduration from the initiation of drawing to the detection of sample bloodby sensor 256 can be used for determine the thickness or viscosity ofsample blood 196. Thick sample blood 196 flows more slowly than thinsample blood 196 under the same conditions of syringe 204.

Returning now to FIG. 14 the illustrated embodiment of hydraulic circuit194' provides a fixed path length over which the movement of the leadingedge of blood sample 196 can be timed. That is, the flow distancebetween sensors 256 and 258 is fixed, and is independent of externaltube lengths such as inlet tube 212. Thus, a measurement of the timerequired for the leading edge of blood sample 196 to pass from sensor256 to sensor 258 can be interpreted in terms of the thickness of theblood sample 196. As a consequence, the thickness measurement isaccurate.

Referring to FIG. 16, another embodiment of a hydraulic circuit 194employs inlet tube 212 connected to syringe 204 through a two way valve273. Initially, two way valve 273 is in a position connecting inlet tube212 to syringe 204. Sample container 52, containing sample blood 196 isplaced under the end of inlet tube 212. Sample blood 196 is drawnthrough inlet tube 212 as far as sensor 256 by syringe 204. The timefrom the initiation of drawing to the sensing of sample blood 196 bysensor 256 is measured by timer 260. Inlet tube 212 is moved to aposition over slide 28 and the action of syringe 204 is reversed,dropping sample blood 196 onto slide 28 to form blood drop 128 thereon.Two way valve 273 is changed to a position connecting syringe 204 totube 228. Syringe 204 is operated to draw in a quantity of washer fluid259 from washer 230. Two way valve 273 is changed to its originalposition connecting syringe 204 to inlet tube 212. Washer fluid 259 isexpelled from syringe 204 to clean sensor 256 and inlet tube 212. Theprocess can then be repeated with another sample blood 196.

Referring to FIG. 17, a smearing glass 132 is held by a glass holder275, which is pivotally secured to a smearing fixture 276 by a shaft278. Shaft 278 is rotatably and removably secured in a notch 280 by thepressing action of a flat spring 282. Glass holder 275, together withshaft 278 can be removed by pulling strongly to the right, as shown inFIG. 17. At an upper portion of smearing fixture 276, a shaft 284pivotally supports an arm 286. A flat spring 288 is pivotally supportedby a shaft 290. A first side of a coil spring 292 is connected tosmearing fixture 276. A second side of coil spring 292 is connected toarm 286. The spring action of coil spring 292 tends to hold arm 286against smearing fixture 276. A first side of a coil spring 296 isconnected to arm 286. A second side of coil spring 296 is connected toflat spring 288. This pulls flat spring 288 against a heel 298 of glassholder 275, while arm 286 is pressed against an upper surface 300 ofglass holder 275. A bearing 302 is rotatably attached to arm 286 by ashaft 304.

The mounting of smearing fixture 276 (not shown) allows it to be movedboth horizontally and vertically in its position in smear generator 60,shown in FIG. 7. This movement can be accomplished by a number ofavailable conventional means, for example, a timing belt to which holder275 is attached and which is hung between two pulleys, one of which isdriven by a stepping motor while the other is fixed to smear generator60.

Because glass holder 275 is held firmly in position between arm 286 andflat spring 288 by coil springs 292 and 296, when smearing fixture 276moves downwards, smearing glass 132 is pressed firmly against slide 28.An angle 308 between smearing glass 132 and slide 28 can be varied toachieve the desired smear thickness by adjusting the downward travel ofsmearing fixture 276. A largest angle 308 between smearing glass 132 andslide 28 occurs when smearing glass 132 lightly touches slide 28.Continuing descent of smearing fixture 276 causes glass holder 275 topivot counterclockwise on shaft 278 against the pressure of flat spring288 and coil springs 292 and 296, so that as smearing fixture 276 islowered, angle 308 becomes more acute while good contact betweensmearing glass 132 and slide 28 is maintained.

Once angle 308 is adjusted to the correct value for the measuredthickness of the blood sample being prepared, smearing glass 132 ispulled along slide 28 with good contact as smearing fixture 276 moveshorizontally in a direction parallel to the surface of slide 28 to smearsample blood 196 on slide 28. Varying the speed with which smearingglass 132 is drawn across slide 28 also controls the thickness of thesmear.

After the blood smear is made, smearing glass 132 is washed in glasswasher 136 (see FIG. 7).

Referring now to FIG. 18 a vertical cross section of smearing fixture276 shows glass holder 275 in position for washing smearing glass 132.

After a smear is made, and slide 28 is moved out of the way, smearingfixture 276 is lowered further until a lever or the like (not shown)blocks downward motion of bearing 302 on arm 286. Further downwardmotion of smearing fixture 276 forces arm 286 to pivot upward aboutshaft 284, pulling flat spring 288 forward with coil spring 296 androtating glass holder 275 and smearing glass 132 to the verticalposition against a stop 306. This places smearing glass 132 in verticalposition appropriate to enter and be washed in washer 136 (FIG. 7) assmearing fixture 276 continues to descend.

Referring to FIG. 19, a light emitter 310, which may be, for example, aninfra red emitting LED, and a light receiver 312, such as a photo diode,are disposed on opposite sides of a slide 28 having a smear 42 on itssurface 316. A light beam 318 from light emitter 310 passes throughsmear 42 and slide 28 at an axis 320 to light receiver 312. When thesurface of slide 28 is clean, substantially all of the light emitted bylight emitter 310 reaches light receiver 312, indicating that no smear42 is present. An alarm output is generated by light receiver 312. Whena smear 42 is present the light received by light receiver 312 isreduced, indicating that a smear 42 has been made and no alarm signal isgenerated.

FIG. 20 shows a graph 324 that represents a relationship betweenincidence angle 319 and a signal voltage level output from lightreceiver 312. The signal level is measured by the output voltage oflight receiver 312 as it moves around axis 320 of slide 28, whilemaintaining its relationship to light emitter 310. In FIG. 19, a brokenline 321 depicts a circle centered at axis 320. Both light emitter 310and light receiver 312 are placed on circle 321. Infrared light fromlight emitting device 310 passes through slide 28 at center axis 320 toreach light receiver 312.

Referring again to FIG. 20, a solid line 326 shows voltage changes inthe output of light-receiving device 312 with no blood smear 42 on slide28. A dotted line 328 represents the voltage changes with a smear 42 onslide 28. Without smear 42, the output voltage declines as the incidenceangle 319 increases. That is, the larger incidence angle 319 gets, thelarger the difference between a signal made with smear 42 and a signalmade without smear 42.

The reason for this is that the amount of light interrupted by particlessuch as blood cells increases as incidence angle 319 increases.

To achieve the desired result, incidence angle 319 must be greater than0 degree and less than 90 degrees. For practical reasons, an angle 319of between 30 degrees and 75 degrees is the preferred embodiment and anangle 319 of between 50 degrees and 70 degrees is the most preferredembodiment.

Referring to FIG. 21, a printer head 322 of printer 142 is positioneddirectly above a slide 28 that is supported on a guide plate 323. Guideplate 323 steps slides 28 under the printer one at a time whereidentifying codes are printed on them.

A holder 324, which is positioned directly under the printer head 322 tohold slide 28 during printing, comprises a pair of arms, 326 and 328.Arms 326 and 328 are pivotally attached to a support 329 by pins 330 and332, respectively. A piston 336, that is driven by a pneumatic source(not shown), extends vertically through support 329. Piston 336 isattached at its topmost end by a connecting pin 338 to crank 339. Crank339 is attached to a pivoted end of arm 328 and slidably contacts alower vertical surface of arm 326. When piston 336 is moved in adirection away from printer head 322, arms 326 and 328 are moved towardeach other by the action of crank 339 and connecting pin 338. A shockabsorber 334, disposed along an inner surface of arm 326, absorbs shockand prevents protrusions 340 and 342, that extend inwardly from the topsof arms 326 and 328, respectively, from breaking slide 28 as they close.Shock absorber 334 may be of any convenient material including, forexample, a rubber or a foam rubber pad.

During operation, when a slide 28 is in position for printing, piston336 is moved in a direction to close arms 326 and 328 on each other,thus placing protrusions 340 and 342 over opposite edges of slide 28. Inthis position, protrusions 340 and 342 hold slide 28 securely againstguide plate 323 while printer head 322 prints an identifying code on theslide.

A ribbon 344 of printer head 322 both deposits ink on slide 28 andabsorbs some of the impact shock of a printer poin 346, therebypreventing slide 28 from being cracked.

The force of the impact of printer pin 346 is sufficient, to crush someof the surface hills 348 of frosted area 96 of slide 28, therebyallowing ink to penetrate the frosting for improved adhesion.

FIGS. 22 and 23 illustrate the effect of the impact of printer pin 346on frosted area 96. FIG. 22 is a greatly magnified representation ofprinter pin 346 poised above ribbon 344. Frosted area 96 of slide 28shows a plurality of hill like projections 348 greatly magnified.

Referring to FIG. 23, when printer pin 346 strikes ribbon 344, the forceof the impact against frosted area 96 is sufficient to crush projections348 driving ink down below the tops of surrounding projections 348, andapplying a permanent identifying code that cannot be washed off slide28.

Advantages of the described embodiment of printer head 322 include theuse of an economical commercially available printer and the use of theimpact of printer pin 346 to drive ink into fine concavities, providingink with good adhesion.

Referring to FIGS. 24 and 25, smeared sample rack 144 comprises acassette body 352 with a handle 354. Cassette body 352 is an openrectangle, having neither top or bottom walls. A plurality of verticalgrooves 356, 356' are arranged in parallel on opposing inner facingsurfaces of side walls 360. The widths of vertical grooves 356, 356' areslightly wider than the thickness of slide 28. Vertical grooves 356,356' extend downward from the topmost edges of side walls 360 and endjust above the bottom edges of side walls 360, forming a series ofparallel slide storage positions 362. The bottom ends 364 of storagepositions 362 prevent slides 28 from dropping through an open bottom 366of cassette body 352.

Smeared sample rack 144 as illustrated, has positions for up to 25slides 28. Slots 368 in both side walls 360 at each storage positionallow air circulation through cassette body 352.

A guide notch 369, horizontally disposed across a lower portion of anend wall 370, engages a guide rail (not illustrated) of a transportationunit to be described.

Handle 354 is a thick wire that is bent to a U-shape. Ends 371 of handle354 are bent inwardly and pivotally inserted into a handle slot 372 oneach of end walls 370 and 374 for attachment to cassette body 352.

Referring to FIG. 26, it can be seen that an enlongated shape of handleslots 372 allows handle 354 to be pulled up (indicated in phantom) forcarrying (not shown).

V-shaped recesses 376 on the outer surfaces of end walls 370 and 374,that extend upward from the lowermost ends of handle slots 372, allowhandle 354 to tilt to the left, as shown in the FIG. 26 when smearedsample rack 144 is positioned for receiving slides 28. V-shaped recess376 allows handle 354 to tilt only in the direction shown, because ofvertical edges 378 that block the movement of handle 354 beyond thevertical position in their direction. When handle 354 is released, itdrops to the tilted position shown.

Because handle 354 can slope as shown, it is possible to attach two ormore smeared sample racks 144 together at side walls 360 for moving orcollecting.

Referring to FIG. 27, there is shown a second embodiment of smearedsample rack 144 from which handle 354 is omitted for purposes ofexplanation. Slot bottoms 380 of slots 372 are modified to extend undervertical edge 378. When handle 354 is released, ends 371 drop to slotbottoms 380, thus forcing handle 354 against vertical edge 378 andurging handle 354 to the desired position when it is released.

In still another embodiment of smeared sample rack 144, shown in FIG.28, the shape of handle 354 is changed. In this embodiment, slots 372are as described in FIG. 26, but handle 354 is unbalanced by putting abend 382 in it in the direction in which it is intended to tilt. Aweight 384 can be added as shown in phantom to further unbalance handle354.

Referring to FIG. 29, a U-shaped transportation unit 386 for smearedsample rack 144 has loading platform 148 with a cassette guide rail 390parallel to its outer edge. Guide rail 390 engages notch 369 of emptysmeared sample racks 144 (shown in FIG. 27). Guide rail 390 holds emptysmeared sample racks 144 in proper alignment and prevents them fromtipping over during transit to track 147 which is disposed at rightangles to loading platform 148.

Smeared sample racks 144 are transported by track 147 to a positionproximal to hand 146 for loading. They are then stepped along track 147,one storage position 362 at a time, as they are loaded with slides 28.When all storage positions 362 are filled, smeared sample rack 144 istransferred to unloader 149, located at an end of track 147, for removalfrom track 147. Guide rail 391 of unloader 149 engages notch 369 ofsmeared sample rack 144 to prevent it from tipping over.

A U-shaped path for smeared sample racks 144 is a simple arrangementmaking efficient use of space.

Blood analyzer system 49 of the invention is a complete apparatus forthe analysis of blood and includes means for holding, transporting,handling and identifying blood samples, automatic blood analysis, andautomatic blood smear generation.

Referring to FIG. 5, in operation, when sample racks 48 loaded withsample containers 52 individually labelled with a bar code identifier,are arranged in loader 44, blood analyzer system 49 is started. Theforemost sample rack 48 is transferred to conveyor 50 and is stepped inthe direction indicated, passing through at least one of a bloodanalyzer 56, a reticulate blood corpuscle analyzer 58 and a blood smeargenerator 60 under the control of controller 62. Conveyor 50 steps onesample container position at a time and pauses at each position to allowblood analysis and sampling procedures to be completed.

Along conveyor 50, from right to left, there are a blood analyzers whichmay include a blood corpuscle analyzer 56 (e.g., Toa Medical ElectronicsNE-8000) and a reticulate red blood corpuscle analyzer 58 (e.g., ToaMedical Electronics R-1000), in addition to a smear generator 60. TheNE-8000 is a blood corpuscle analyzer able to determine thefive-classification data of white blood corpuscles in a blood sample, aswell as to count blood components. The R-1000 is a reticulate red bloodcorpuscle analyzer with which a count of reticulate red blood corpusclesand their ratios in the blood sample are obtained.

Sample rack 48, conveyed by conveyor unit 50, stops at first bloodanalyzer 56 where a bar code identifier on the first sample container 52is read by bar code reader 70. To assure that the bar code can be read,a rotator assembly 71 (shown in FIG. 6) slowly rotates sample container52. First blood analyzer 56 records the bar code identifier and reportsit and the results of its analysis of the blood sample contained insample container 52 to system controller 62. A portion of the samplecontained in sample container 52 is removed for analysis by first bloodanalyzer 56 using a needle and a hydraulic blood drawing circuit notshown. First blood analyzer 56 repeats this procedure for each samplecontainer 52 stepped to it until all of the sample containers 52 insample rack 48 have been analyzed. Sample rack 48 is then transported tosecond blood analyzer 58 which reads and records the bar code identifierof the sample containers 52 brought to it and reports the bar code andthe results of each analysis to system controller 62 as did first bloodanalyzer 56.

Next, rack 48 is transported to smear generator 60. The bar code of eachsample container 52 is read by bar code reader 70 of smear generator 60and reported to controller 62. System controller 62 checks the reportedbar code against the analyses reported for that bar code by bloodanalyzers 56 and 58. If the analyses indicate a normal blood sample, itssample container 52 is moved along and the next sample container steppedto smear generator 60. When system controller 62 identifies the bar codeof an abnormal blood sample, smear generator 60 is caused to make asmeared blood sample 138.

Sample racks 48 that have passed smear generator 60 on conveyor 50 arethen transferred to unloader 66 for removal from blood analyzer system49.

Referring to FIGS. 30 and 7, when the identifier of a sample container52, read by bar code reader 70, is that of an abnormal blood sample,system controller 62 initiates the generation of a smeared blood sample138. Conveyor 50 positions sample rack 48 with the subject samplecontainer in position under hydraulic circuit 194, which draws sampleblood 196 as shown in FIG. 13 from sample container 52 and drops a blooddrop 128 on a slide 28. Blood drop 128 is then smeared by smearing glass132 on slide 28 to form smeared blood sample 138. Smeared blood sample138 is dried by fan 140. A smear detector 40 then checks that a smearedblood sample 138 has been properly prepared. When smear detector 40detects a blank slide 28, an alarm is sounded, indicating a systemfailure.

The amount of sample blood 196 dispensed, the angle between smearingglass 132 and slide 28, and the smearing speed of smearing glass 132 aredetermined for each sample blood 196 by system controller 62 using datafrom blood analyzers 56 and 58. These smearing conditions aretransmitted by system controller 62 to smeared sample generator 60 tocontrol smearing glass 132.

The thickness of sample blood 196 may be determined by a blood analyzer56 based, for example, on a percentage of hemoglobin present in sampleblood 196, because the amount of hemoglobin correlates with thickness orviscosity. A high percentage of hemoglobin indicates a thick sampleblood 196.

The time required by hydraulic circuit 194 to draw a sample blood 196from sample container 52 can also used to determine the thickness ofsample blood 196. A thick sample blood 196 is drawn more slowly than athinner sample blood 196.

System controller 62 controls the angle of smearing glass 132 againstslide 28 and its smearing speed across slide 28 to prepare smeared bloodsamples 138 of consistent thickness regardless of characteristics ofsample blood 196 being smeared.

For thin sample blood 196, compared to a standard sample blood 196,system controller 62 commands at least one of the following adjustments:

(1) The amount of sample blood 196 to be smeared is increased,

(2) The angle of smearing glass 132 is set larger, and

(3) The pulling speed is increased.

For thick sample blood 196, compared to a standard sample blood 196,system controller 62 commands at least one of the following adjustments:

(1) The amount of sample blood 196 to be smeared is decreased,

(2) The angle of smearing glass 132 is decreased, and

(3) The pulling speed is reduced.

Slides 28 for supporting smeared blood samples 138 are taken from aslide storage source such as slide stack 92 and moved through the smeargeneration process by slide conveyor 94.

Under the control of system controller 62, through an input outputinterface 392, printer 142 prints an identifying code on a frosted area96 of slide 28d that corresponds to the bar code of sample container 52from which sample blood 196 was taken.

A hand 146 then removes finished slide 28 from slide conveyor 94 andplaces it in smeared sample rack 144 for removal from the blood analyzersystem 49.

As can be seen in FIG. 7, after each smeared blood sample 138 is made,smearing glass 132 is washed in glass washer 136, and dropper 130 iswashed in dropper washer 134. In some embodiments of hydraulic circuit194 a separate washing system is used, refer to FIGS. 14 and 15.

The present invention improves the efficiency of blood analysis comparedwith the prior art. Further, this system is flexible. If instructionsare given to the system controller in advance, only selected samples aremeasured by the blood analyzers and smeared.

Improved efficiency also results from a smear generator 60 that is fullyintegrated into the remainder of blood analyzer system 49.

Flexibility is enhanced by the ability to program required analysis foreach sample blood 196 into system controller 62.

Waste is eliminated because smeared blood samples 138 are prepared onlyfor abnormal blood as indicated by blood analyzers 56 and/or 58.

Sample containers 52 can be capped with a rubber stoppers withoutinterfering with the blood sampling process, thus preventing thepossible spread of blood infections.

The fully automatic operation of the blood analyzer system through smeargeneration saves labor cost.

Quality blood smears are assured because the correct blood smearingconditions are selected for each sample because the system utilizes anumber of means for determining the thickness of individual samples.

Having described preferred embodiments of the invention with referenceto the accompanying drawings, it is to be understood that the inventionis not limited to those precise embodiments, and that various changesand modifications may be affected therein by one skilled in the artwithout departing from the scope or spirit of the invention as definedin the appended claims.

What is claimed is:
 1. A smeared sample rack comprising:a cassettehaving two opposing side walls; a U-shaped handle; cooperating means insaid handle and said cassette for pivotably mounting said handle to eachside wall of said cassette; said cooperating means permitting first andsecond positions for said handle on said cassette; said first positionbeing substantially vertical; said second position being inclined at anangle from said vertical; said cooperating means including a recess ineach side wall of said cassette; said recess having a substantiallyvertical side; an inclined side and a handle slot; said handle beingbent inwardly and pivotally inserted into said handle slot on eitherside wall of said cassette by a rotatable member; said rotatable membercontacting said vertical side of said recess in said first position; andsaid rotatable member contacting said inclined side of said recess insaid second position.
 2. Apparatus according to claim 1, furthercomprising means for urging said handle into said second position; saidmeans for urging being disposed in said cooperating means.
 3. Apparatusaccording to claim 2, wherein said means for urging said handle intosaid second position includes a substantially semicircular opening onsaid vertical side of said recess.
 4. Apparatus according to claim 1,wherein said recess on either side wall of said cassette is V-shaped. 5.Apparatus according to claim 4, further comprising means for urging saidhandle into said second position which are disposed on said handle. 6.Apparatus according to claim 5, wherein said means for urging includesat least one bend in said handle, said at least one bend overbalancingsaid handle toward said second position when said handle is in saidfirst position, by placing said bend in said handle in the inclineddirection of said second position.
 7. Apparatus according to claim 5,wherein said means for urging includes at least one weight affixed to aside of said handle, said at least one weight being effective foroverbalancing said handle toward said second position when said handleis in said first position.
 8. Apparatus according to claim 4, furthercomprising means for urging said handle into said second positiondisposed in said cooperating means.
 9. Apparatus according to claim 8,wherein said means for urging said handle into said second positionincludes a substantially semicircular opening on said vertical side ofsaid recess.
 10. Apparatus according to claim 9, further comprisingmeans for urging said handle into said second position which aredisposed on said handle.
 11. Apparatus according to claim 10, whereinsaid means for urging includes at least one bend in said handle, said atleast one bend overbalancing said handle toward said second positionwhen said handle is in said first position, by placing said bend in saidhandle in the inclined direction of said second position.
 12. Apparatusaccording to claim 10, wherein said means for urging includes at leastone weight affixed to a side of said handle, said at least one weightbeing effective for overbalancing said handle toward said secondposition when said handle is in said first position.